@Sisir Yes, it works perfectly fine. We just sent out a message to our mailing list yesterday and everything came through properly. It was a multipart message and the boundary entry was only once (WP core adds 2 boundary entries, scrambling the headers...) -- Note that this doesn't mean that all your messages will end up primiarly in the inbox, it could end up in the spam folder depending on a number of factors, all unrelated to this issue.
